Holiday Gift Guide 2010 week 4 on GamersGate has dozens of titles on sale along with a buy four, pay for three promotion. There are more than 1000 titles on sale in the Steam Holiday Sale. Direct2Drive has three different coupon codes, offering up to 25% off, depending on how much you spend.
Virtually the entire catalogue of DRM-free good old games at GOG.com is on sale for up to 50% off through the new year, and they are giving away Tyrian 2000 for free. The Humble Indie Bundle #2 offers the chance to pay what you want for a bundle of Braid, Cortex Command, Machinarium, Osmos, and Revenge of the Titans, once again allowing you to give some of your contribution to charity. Two or more eligible games on the EA Store are 50% off. There are a bunch of strategy games on sale on Matrix Games.

Dev wrote on Dec 23, 2010, 09:14:I beg to differ. Both the L4D games a new player benefits hugely from having played at least 1 campaign in single player. Otherwise you end up with people who don't know to right click to keep off mobs, or how to turn off flashlight near witch. Valve needs a single player infected trainer campaign too so people can learn how to pounce as a hunter (they walk around trying to scratch). Its that use of the word "any" that gets me thinking of counter examples